[The Englishmen already in 1862 succeeded in getting a sultan to sign a treaty to abolish slavery. This act formalized but did not resolve the flow of slaves.
Slight results were obtained when, in the 1873, a treaty was signed between the sultans of Muscate (Oman) and Zanzibar which prohibited slavery with the exception of those of the sultan's personal property. This fact led to the concern, especially by the sultan of Zanzibar, to see the local economy reduced, so it was not fully implemented as agreed and the English navy, after one month imposed the naval blockade that was followed by Germany in the 1888 and later from Italy.
Slavery was finally abolished in Zanzibar in 1897]
Source: Military Navy
